provide a way to control argv[0] of the spawned process #472
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@mirabilos Why would it be needed to treat this separately, why not just use existing API: pty.spawn('/bin/sh', ['-sh', ...], ...) |
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jerch dixit:
***@***.*** Why would it be needed to treat this separately, why not just use existing API:
```typescript
pty.spawn('/bin/sh', ['-sh', ...], ...)
```
AIUI in the existing API, the first element of the args array
corresponds to argv[1], not argv[0]. At least from reading one
of the testcases in this repo this is what I think is the case.
So, it must be a new API because changing this would break all
existing users.
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@mirabilos Thx, found the piece of code, where it gets copied over as argv[0]. Is that '-' convention of API-wise I see 2 possible ways to support it:
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Hi jerch,
***@***.*** Thx, found the piece of code, where it gets copied over as
***@***.***[0]. Is that '-' convention of `login` specced somewhere (maybe in
@posix?) or at least known to work in all major POSIX systems with all
***@***.***?
I don’t have the standard or place in it handy, but I do know that this
is the normal behaviour of login, ssh¹, xterm² etc. when they want to
make a login shell.
① search for “this is a login shell” in
http://cvsweb.openbsd.org/src/usr.bin/ssh/session.c?rev=1.328
② search for “shname_minus” in
http://www.mirbsd.org/cvs.cgi/X11/xc/programs/xterm/main.c?rev=1.5
Do you have some more insights here, e.g. how does a non shell
***@***.*** deal with the '-'?
Most executables don’t inspect argv[0] at all. Multi-call binaries do;
these like busybox usually have entries for both "sh" and "-sh" (usually
the basename only is inspected). Other multi-call binaries do NOT have
special handling for a leading hyphen-minus, for example, I know of a
true/false binary that exits 0 if argv[0][0] is ‘t’, 1 if it is ‘f’, so
adding this for all executions is not correct. It also should not be
added to a shell that invokes a command (like sh -c "echo 123").
How does it get "translated" for the new
***@***.***, will it just see the '-' as first char in argv and do
***@***.*** things on its own?
Exactly. In most invocations, argv[0] will just be the name of the
program invoked, which can be the shell (often with full pathname,
e.g. "/bin/sh") or a script (often relative, "./foo.sh"). Login shells
will generally get "-/bin/sh" or "-sh" instead, depending on the caller.
Search for “determine the basename” in
http://www.mirbsd.org/cvs.cgi/src/bin/mksh/main.c?rev=1.377 if you’re
interested in seeing how mksh does this (basically, if argv[0] and/or
basename(argv[0]) begin with a hyphen-minus, FLOGIN is set).
API-wise I see 2 possible ways to support it:
- a boolean flag `loginShell` in options, which adds the '-' to
argv[0], if it is meant as login shell (smooth upgrade path, but less
powerful and semantically slightly wrong if we dont have a shell at
all)
- extend argv to always contain arvg[0] explicitly (API breakage, thus
works only as major change, more powerful in the long run as it feeds
things directly to `execvp` also allowing for weird
interpreter/script execution)
I see two more, the first of them preferred IMHO:
- extend opts with a string option that can set argv[0]; continue to
use the program path if this option is not passed
- add a new API, e.g. spawna(), whose argv contains argv[0] explicitly
Both won’t break any existing code.
bye,
//mirabilos
--
„Cool, /usr/share/doc/mksh/examples/uhr.gz ist ja ein Grund,
mksh auf jedem System zu installieren.“
-- XTaran auf der OpenRheinRuhr, ganz begeistert
(EN: “[…]uhr.gz is a reason to install mksh on every system.”)
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Looking at interface IPtyForkOptions {
...
argv0: undefined | string;
} |
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jerch dixit:
Looking at `child_process` its API supports an optional `argv0` setting in options:
```typescript
interface IPtyForkOptions {
...
argv0: undefined | string;
}
```
which defaults to the given command if not set.
Oh, so this is already there. I hadn’t seen it, but then, I only
quickly searched through the code to spot the approximate place.
So yeah this might be the best way to deal with it.
If this works, then, indeed.
Thanks,
//mirabilos
--
FWIW, I'm quite impressed with mksh interactively. I thought it was much
*much* more bare bones. But it turns out it beats the living hell out of
ksh93 in that respect. I'd even consider it for my daily use if I hadn't
wasted half my life on my zsh setup. :-) -- Frank Terbeck in #!/bin/mksh
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Tyriar
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To properly fix microsoft/vscode#123332 node-pty must provide a way to control
argv[0]of the spawned process, that is, instead of…… which internally does an…
… vscode must do something like…
… which internally does an…
… so a new API will be needed, unless this can be put into
optionssomehow, perhaps…The text was updated successfully, but these errors were encountered: